Date: Sat, 26 Jan 2013 22:02:47 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Coolant Overpressurization / Head Gasket Leak
In-Reply-To: <vanagon%2013012620244316@GERRY.VANAGON.COM>
Content-Type: text/plain; charset="us-ascii"
You definitely need to do some testing to try to determine why the
compression is down on those two cylinders. Before pulling the heads I would
check the torque on the head nuts. Internal leaks between the tops of the
cylinders and heads are really due to failure of the studs to keep the heads
down under those compressive/pressure loads and the temperature changes of
the engine parts. I have repaired a number of internal leak issues by
re-torqueing the heads. The other failure point is cracked heads allowing
the gasses into the cooling system. Coolant-hydrocarbon testing is not
always effective for diagnosing. As part of the leak down test, by pass the
gauge and apply full shop air pressure to the cylinders (secure the
crankshaft securely) may make the leak obvious.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Walter Houle
Sent: Saturday, January 26, 2013 8:08 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Coolant Overpressurization / Head Gasket Leak
The morning after the 300 mile drive home from BBB I noticed that the
coolant overfolw tank was full and overflowing a few drips. The expansion
tank was also 100% full. I opened the pressure cap a little bit at a time
and a lot of coolant pushed out - this on a stone cold engine that was
sitting for 12 hours. It looks like I have an internal head gasket leak.
The strange part was that the van ran strong all the way home and didn't
show any obvious signs of overheating. We stopped and checked it twice along
the way, no drips, no smell, and no excess heat. The temp gauge was over the
right edge of LED and it behaved normally, up a tad on the climbs, and down
a tad on the descents, just like always. I did a compression test today and
it was 170-170-140-150. Its been low on 3 & 4 like that for a while, last
test was 6 months ago, but this is the first time I've had coolant issues.
I will try a hydrocarbon sniff of the coolant and then a leakdown test to
confirm. I've read a lot in the archives, and its looking more and more like
its a compression leak, and it looks like it is only occuring under load.
The heads are old and have never been off, original VW factory rebuild, 15
years and 75K miles ago.
Yes, this is way overdue and I should have taken care of this earlier.
I am assumming new heads are in order, and I'm hoping that is going to be
it. What about the rest of the engine? If it was pushing coolant away from
the cylinders, it was doing it for a long period of time. WHat else should I
be looking at?
Thanks,
Walter
1985 Vanagon 1.9 in San Diego
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